/*
 * @Author: long-xinyu2 2192763423@qq.com
 * @Date: 2025-03-11 18:47:55
 * @LastEditors: long-xinyu2 2192763423@qq.com
 * @LastEditTime: 2025-04-02 17:55:42
 * @FilePath: \algorithm\algorithm-training\2025_3_11.cpp
 * @Description: 这是默认设置,请设置`customMade`, 打开koroFileHeader查看配置 进行设置: https://github.com/OBKoro1/koro1FileHeader/wiki/%E9%85%8D%E7%BD%AE
 */
#include<iostream>
#include<cstring>
#include<vector>
#include<map>
#include<cstdio>
#include<algorithm>
#include<string>
#include<string.h>
#include<queue>
#include<math.h>
#include<set>
#include<functional>
using namespace std;
#define int long long
//using i128 = __int128_t;
inline int inc(int x, int v, int mod) { x += v;return x >= mod ? x - mod : x; }//代替取模+
#define endl '\n'
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> PII;

const int N = 2e3 + 10, M = 1e5 + 10;

inline int read()
{
    int x = 0, f = 1;
    char ch = getchar();
    while (ch < '0' || ch > '9')
    {
        if (ch == '-')
            f = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')
        x = x * 10 + ch - '0', ch = getchar();
    return x * f;
}

bool check(int x)
{
    for(int i = 2; i <= sqrt(x); i ++){
        if(x % i == 0)
        {
            return false;
        }
    }
    return true;
}

void solve()
{
    int n;
    cin >> n;
    string s;
    cin >> s;
    if(n == 1)
    {
        cout << -1 << endl;
        return;
    }
    s = ' ' + s;

    map<char,int>mp;
    for(int i = 1; i <= n; i ++)
    {
        if(s[i] == 'L') mp['L']++;
        if(s[i] == 'T') mp['T']++;
        if(s[i] == 'I') mp['I']++;
    }
    if(mp['L'] == mp['I'] && mp['L'] == mp['T'])
    {
        cout << 0 << endl;
        return;
    }
    vector<int>ans;
    int m = (int)'L' + (int)'T' + (int)'I';
    for(int i = 2; i <= n; i ++)
    {
        if(s[i - 1] == s[i]) continue;
        int p = i - 1;
        char x = s[i - 1];
        char z = s[i];
        char y = m - (int)x - (int)z;
        mp[y]++;
        ans.push_back(p);
        while(mp[x] != mp[y] || mp[y] != mp[z] || mp[z] != mp[x])
        {
            if(mp[x] > mp[z])
            {
                ans.push_back(p);
                mp[z]++;
                swap(z,y);
            }
            else
            {
                ans.push_back(++p);
                mp[x]++;
                swap(x,y);
            }
        }
        break;
    }
    if(mp['L'] != mp['T'] || mp['I'] != mp['L'] || mp['T'] != mp['I'])
    {
        cout << -1 << endl;
        return;
    }
    cout << ans.size() << endl;
    for(int i = 0; i < ans.size(); i ++)
    {
        cout << ans[i] << endl;
    }
}
signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    int tt;
    cin >> tt;
    //tt = 1;
    while (tt--)
    {
        solve();
    }
}